Cardiac Baroreflex during the Postoperative Period in Patients with Hypertension

Background Patients with essential hypertension show altered baroreflex control of heart rate, and during the perioperative period they demonstrate increased circulatory instability. Clonidine has been shown to reduce perioperative circulatory instability. This study documents changes in measures of heart rate control after surgery in patients with essential hypertension and determines the effects of clonidine on postoperative heart rate control in these patients. Methods Using a randomized double-blind placebo-controlled design, 20 patients with essential hypertension (systolic pressure >160 mm Hg or diastolic pressure >95 mm Hg for > or =1 yr) were assigned to receive clonidine (or placebo), 6 microg/kg orally 120 min before anesthesia and 3 microg/kg intravenously over 60 min before the end of surgery. The spontaneous baroreflex ("sequence") technique and analysis of heart rate variability were used to quantify control of heart rate at baseline, before induction of anesthesia, and 1 and 3 h postoperatively. Results Baroreflex slope and heart rate variability were reduced postoperatively in patients given placebo but not those given clonidine. Clonidine resulted in greater postoperative baroreflex slope and power at all frequency ranges compared with placebo (4.9+/-2.9 vs. 2.2+/-2.1 ms/mm Hg for baroreflex slope, 354+/-685 vs. 30+/-37 ms2/Hz for high frequency variability). Clonidine also resulted in lower concentrations of catecholamine, decreased mean heart rate and blood pressure, and decreased perioperative tachycardia and hypertension. Conclusions Patients with hypertension exhibit reduced heart rate control during the recovery period after elective surgery. Clonidine prevents this reduction in heart rate control. This may represent a basis for the improved circulatory stability seen with perioperative administration of clonidine.

Download Full-text

RESPOSTAS HEMODINÂMICAS DO MÉTODO PILATES EM HIPERTENSOS: UMA REVISÃO SISTEMÁTICA

Revista Brasileira de Ciência e Movimento ◽

10.31501/rbcm.v27i4.10626 ◽

2019 ◽

Vol 27 (4) ◽

pp. 219

Author(s):

Leonando Pedro Pereira Da Costa ◽

Gabriela Dos santos ◽

Patrícia Haas ◽

Renato Claudino ◽

Ana Inês Gonzáles

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Young Adult ◽

High Blood Pressure ◽

Pulse Rate ◽

Rate Control ◽

Diastolic Pressure ◽

Systolic Pressure ◽

Heart Rate Control ◽

Exercise Movement Techniques

Objetivo: levantar na literatura atual, estudos relevantes que identifiquem as possíveis respostas hemodinâmicas encontradas em indivíduos hipertensos praticantes do Método Pilates. Materiais e Métodos: Pesquisa de revisão sistemática conduzida conforme as recomendações PRISMA em cinco bases de dados eletrônicas (PEDro, PubMed, SciELO, LILACS e Cochrane), disponibilizado desde o início das bases até Março de 2019, com descritores do dicionário MESH conforme segue: [(“Adult” OR “Young adult” OR “Middle Aged” OR “Aged” OR “Elderly”) AND (“exercise movement techniques” OR “Pilates-Based Exercises” OR “Pilates Training”) AND (“Hemodynamics” OR “Heart Rate” OR “Cardiac Chronotropy” OR “Heart Rate Control” OR “hypertension” OR “Blood Pressure” OR “High Blood Pressure” OR “Systolic Pressure” OR “Diastolic Pressure” OR “High Blood Pressure” OR “Pulse Rate Determination”)], posteriormente ajustado para as demais bases. Busca complementar manual nas referências dos artigos incluídos na pesquisa e no Google Scholar. Foram incluídos estudos de intervenção, com indivíduos de idade maior ou igual a 18 anos; diagnóstico de hipertensão arterial sistêmica (HAS); que tenham sido submetidos a exercícios de pilates solo e/ou pilates aparelhos como método de intervenção e incluído a descrição de análise das variáveis hemodinâmicas de pressão arterial (PA), frequência cardíaca (FC) e duplo produto (DP). Resultados: Após processo de seleção foi selecionado apenas um único estudo que tenha contemplado todos os critérios de elegibilidade, totalizando 44 indivíduos do sexo feminino, com média de idade de 50,5 anos (±6,3 anos), hipertensas com utilização de medicação, onde 22 foram submetidas ao pilates solo e 22 permaneceram no grupo controle. O estudo apresentou resultados positivos na frequência cardíaca (FC), pressão arterial (PA) e no duplo-produto (DP) em comparação ao grupo controle. Conclusão: O Mat pilates pode ser um método aplicável e hemodinamicamente em pacientes com HAS, entretanto, novos estudos devem ser realizados para a confirmação dos achados.

Download Full-text

Impaired parasympathetic heart rate control in mice with a reduction of functional G protein βγ-subunits

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00565.2001 ◽

2002 ◽

Vol 282 (2) ◽

pp. H445-H456 ◽

Cited By ~ 34

Author(s):

Josef Gehrmann ◽

Michael Meister ◽

Colin T. Maguire ◽

Donna C. Martins ◽

Peter E. Hammer ◽

...

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Transgenic Mice ◽

G Protein ◽

Rate Control ◽

Sinus Node ◽

Physiological Role ◽

Heart Rate Control ◽

Electrophysiological Studies

Acetylcholine released on parasympathetic stimulation slows heart rate through activation of muscarinic receptors on the sinus nodal cells and subsequent opening of the atrial muscarinic potassium channel (KACh). KACh is directly activated by G protein βγ-subunits. To elucidate the physiological role of Gβγ for the regulation of heart rate and electrophysiological function in vivo, we created transgenic mice with a reduced amount of membrane-bound Gβ protein by overexpressing nonprenylated Gγ2-subunits in their hearts using the α-myosin heavy chain promoter. At baseline and after muscarinic stimulation with carbachol, heart rate and heart rate variability were determined with electrocardiogram telemetry in conscious mice and in vivo intracardiac electrophysiological studies in anesthetized mice. Reduction of the amount of functional Gβγ protein by >50% caused a pronounced blunting of the carbachol-induced bradycardia as well as the increases in time- and frequency-domain indexes of heart rate variability and baroreflex sensitivity that were observed in wild types. In addition, sinus node recovery time and inducibility of atrial arrhythmias were reduced in transgenic mice. Our data demonstrate in vivo that Gβγ plays a crucial role for parasympathetic heart rate control, sinus node automaticity, and atrial arrhythmia vulnerability.

Download Full-text

Alcohol: Effect on Blood Pressure and Predisposition to Hypertension

Clinical Science ◽

10.1042/cs061373s ◽

1981 ◽

Vol 61 (s7) ◽

pp. 373s-375s ◽

Cited By ~ 9

Author(s):

P. D. Arkwright ◽

L. J. Beilin ◽

I. Rouse ◽

B. K. Armstrong ◽

R. Vandongen

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Essential Hypertension ◽

Alcohol Consumption ◽

Diastolic Pressure ◽

Systolic Pressure ◽

Threshold Effect ◽

Health Questionnaire ◽

Government Employees ◽

Weekly Alcohol Consumption

1. The association between alcohol consumption and blood pressure was studied in 491 Government employees. The men, aged 21–45 years, volunteered to complete a health questionnaire and submitted to standardized measurements of blood pressure, heart rate and body size. 2. Average weekly alcohol consumption correlated with systolic pressure (r = 0.18, P < 0.001) but not with diastolic pressure. Systolic pressure increased progressively with increasing alcohol consumption with no obvious threshold effect. The effect of alcohol was independent of age, obesity (Quetelet's index) or cigarette smoking. 3. Results indicate that alcohol ranks close to obesity as a preventable cause of essential hypertension in the community.

Download Full-text

P5985New aspects of management of patients with long-term persistent atrial fibrillation before extracardiac interventions

European Heart Journal ◽

10.1093/eurheartj/ehz746.0706 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

O Dzhioeva ◽

E Resnik ◽

I Nikitin

Keyword(s):

Atrial Fibrillation ◽

Heart Rate ◽

Anticoagulant Therapy ◽

Rate Control ◽

Elective Surgery ◽

Oral Anticoagulants ◽

Direct Oral Anticoagulants ◽

Persistent Atrial Fibrillation ◽

Heart Rate Control

Abstract Surgery in patients with atrial fibrillation is always an additional risk of thromboembolic complications. In the modern era of direct oral anticoagulants, the risk of bleeding is much lower, due to the lack of need for a Bridge, but at the same time, there is no clear position on the strategy of management of patients with long-term current atrial fibrillation in the tactics of rhythm control or heart rate control. In our clinic we examined 772 before surgical intervention high risk. Of these, atrial fibrillation was diagnosed in 366 patients. 121 patients had a persistent or long-persistant form of arrhythmia. To determine the tactics, we performed a transesophageal echocardiographic study to assess intracardiac hemorheology. 109 studies were performed. 35 patients received rivaroxaban, 29 dabigatran, 19 apixaban, 26 patients did not receive anticoagulant therapy. Disorders of intracardiac hemorheology that do not allow to perform a planned cardioversion, such as blood clots and spontaneous contrast 3–4 degrees, were detected in 78% of patients not receiving anticoagulant therapy, 56% of patients receiving dabigatran, 52% of patients receiving rivaroxaban and 38% of patients receiving apixaban. Among patients with disorders of intracardiac hemorheology, unreasonably reduced doses were taken by 78% of patients. Patients with thrombotic disorders proposed to enter the perioperative period in accordance with the strategy of heart rate control and correction doses of anticoagulant therapy. Thus, based on our observations, we recommend transesophageal echocardiography before elective surgery in all patients with persistant AF to determine the feasibility of restoring the sinus rhythm before surgery.

Download Full-text

Effects of Clonidine and Hydrochlorothiazide on the Cardiovascular Response to Mental Stress in Adolescent Hypertension

Clinical Science ◽

10.1042/cs063455s ◽

1982 ◽

Vol 63 (s8) ◽

pp. 455s-458s ◽

Cited By ~ 9

Author(s):

Bonita Falkner ◽

Gaddo Onesti ◽

Melton B. Affrime ◽

David T. Lowenthal

Keyword(s):

Heart Rate ◽

Essential Hypertension ◽

Mental Stress ◽

Diastolic Pressure ◽

Cardiovascular Response ◽

Systolic Pressure ◽

Cardiovascular Responses ◽

Plasma Noradrenaline ◽

Lower Plasma ◽

Adrenergic Activity

1. The effects of clonidine and hydrochlorothiazide on the cardiovascular responses to mental stess were compared in 29 adolescents with essential hypertension. 2. Clonidine therapy was associated with lower diastolic pressures, heart rate and noradrenaline in response to mental stress. By contrast, hydrochlorothiazide resulted in the reduction of systolic pressure only. The mental stress testing produced a greater absolute diastolic pressure response and higher plasma noradrenaline on hydrochlorothiazide therapy. 3. Juveniles with essential hypertension may be more sensitive to central control of blood pressure and more resistant to diuretics. 4. The reduced diastolic pressure and heart rate response to central stimuli during clonidine therapy may be related to decreased adrenergic activity, as indicated by lower plasma noradrenaline.

Download Full-text

Heart rate variability biofeedback as a behavioral neurocardiac intervention to enhance vagal heart rate control

American Heart Journal ◽

10.1016/j.ahj.2005.03.015 ◽

2005 ◽

Vol 149 (6) ◽

pp. 1137.e1-1137.e7 ◽

Cited By ~ 127

Author(s):

Robert P. Nolan ◽

Markad V. Kamath ◽

John S. Floras ◽

Jill Stanley ◽

Clement Pang ◽

...

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Rate Control ◽

Heart Rate Control ◽

Heart Rate Variability Biofeedback ◽

Vagal Heart Rate Control

Download Full-text

EFFECTS OF WEAK EXTERNAL MECHANICAL FORCE STIMULATION ON THE HEART RATE VARIABILITY OF RATS

Biomedical Engineering Applications Basis and Communications ◽

10.4015/s1016237204000438 ◽

2004 ◽

Vol 16 (06) ◽

pp. 313-321 ◽

Cited By ~ 2

Author(s):

HSIN HSIU ◽

PIN-TSUN CHAO ◽

TSE-LIN HSU ◽

WEI-CHEN HSU ◽

WEI-KUNG WANG

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Mechanical Stimulation ◽

Diastolic Pressure ◽

Systolic Pressure ◽

Circulatory System ◽

Mechanical Force ◽

Arterial System ◽

Conducting System ◽

System Effect

Motivation: The heartbeat is driven by electric signals generated inside the heart, the cardiac conducting system plays an important role. Although there are pharmacological and electrical methods working on this conducting system, effect of mechanical stimulation has rarely been discussed. Methods: We used waterbed (size 60×40×10 cm) as a media to study the heart rate variability (HRV) affected by beating the bed with weak mechanical force with 0.5-mm-Hg amplitude. The waterbed is specially designed to raise the transmission efficiency for sound wave. Results: Among 7 studies on 5 rats, there were almost no changes in diastolic pressure, systolic pressure and heart rate, but average of CV (coefficient of variance) of 15-minute heart rate sequences increased from the control value 0.0098±0.0023 (mean±SD) to 0.0119±0.0032 (mean±SD) during the stimulation and decreased to 0.0078±0.0020 (mean±SD) in 15 minutes after the stimulation [p values (paired t-test, both compared with the control) < 0.006 and < 0.0007 respectively]. Discussion: Here we show that such a weak mechanical stimulation was sufficient to affect the circulatory system. Since the effect is not directly acting on the conducting system, this small power may influence the arterial system through resonance mechanism.

Download Full-text